[1] S.K. PAL, R. A. KING, A.A. HASHIM. Automatic gray level thresholding though index of fuzziness and entropy[J]. Pattern Recognition Letters, 1983, 1(3): 141-146.
[2] C.A. MURTHY, S.K. PAL. Bounds for membership function: A correlation-based approach[J]. Information Sciences, 1992,65(2): 143-171.
[3] Chivukula A. MURTHY, Sankar K. PAL. Histogram thresholding by minimizing graylevel fuzziness[J]. Information Sciences,1992, 60(2): 107-135.